Transmitter-mouthpiece.



S. S. SONNEBORN.

TRANSMITTER MOUTHPIEGE.

nrmoumn rum) mm; 21, 1911.

1,031,297, A Patented July 2, 1912.

5 me Mop SOL S. SONNEBOBN, 0F BROOKLYN, NEW YORK.

TBANSM ITTEB-MOUTHPIEGE.

Specification of Letters Patent.

Patented July 2, 1912.

Application filed June 27, 1911. Serial No. 685,574.

- To all whom it may concern:

Be it known that I, Son S. SoNNEBoRN, a citizen of the United States, and resident of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Transmitter-Mouth pieces, of which the following is a specification.

This invention relates to an improved mouthpiece for a telephone transmitter.

The usual mouthpiece employed in telephonic apparatus comprises a bell shaped or flaring horn which on account of its shape is exposed to breakage, and is furthermore particularly adapted to collect dust and dirt, due to the fact that it projects upwardly at an angle and traps all the dust and dirt fallin within its open end. It is moreover so difficult to clean that the mouthpieces are seldom actually cleaned except by the agents of the telephone company to whom this service is an item of considerable cost. Moreover the breath of the user condenses on the interior, causing public telephones to be covered with an unsanitary deposit, dangerous to the health and offensive in any case. A variety of sanitary devices have been suggested or used, but the expense and trouble of these attachments is considerable.

It is the object of my invention to provide a mouthpiece which has fully as high efficiency for every purpose as the mouthpieces now in use, and which has an increased efiiciency for certain purposes, such as eliminating extraneous noises; which is furthermore compact so as to take up but little room in use; which is very strong and durable and not liable to breakage; which is absolutely sanitary, not collecting the dust and dirt in the first place, and so formed as to permit complete cleaning at any time with no other manipulation than rubbing over the surface with the ball or palm of the hand.

It is furthermore an object of the invention to provide a mouthpiece which is adaptembodying the principles of my invention; Fig. 2, shows a slightly modified form; Fig. 3, shows a mouthpiece having a metallic threaded collar, and Fig. 4, shows a mouthpiece embedded integral. with a face plate adapted to fit over any ordinary transmitter arm or frame.

It is of course a fundamental condition that sufiicient sound volume or sound energy must be somehow carried into the interior of the transmitter to properly vibrate the diaphragm. So far as I am aware the attempts at making the mouthpiece sanitary have been mainly in the direction of providing an interponent membrane. I have found that it is possible by the use of a mouthpiece of double reversed conical shape to so concen- :trate the sound at a single point or axis that the requisite volume may be carried through a very small hole or opening, provided this hole or opening is not of very great length. The result is to concentrate the sound with great intensity at a point which is very close to the apex of the opposed cone. By my invention I provide directly at this point a small opening 2 which is sufiicient to carry a large volume of sound on account of the this particular locality. The result is that a very small but intense column of sound is carried through the small opening, the length of this opening being so small that the friction of the air vibration against the sides is negligible. The opening expands into the enlarged interior cone 3 behind the outside cone and acts upon the transmitter diaphragm just like any sound expanding from a small or local point. It is well known that quite intense sounds frequently emanate from a very small point or locality, as is evidenced by the loud cries of certain small birds. With similar effect, by the present invention a flat wave of sound 1s sharply concentrated at a point directly in front of a very short tubular aperture, and the intensity of the vibration at this aperture makes up for the lack of its size.

On account of the comparatively flat nature of the cone 1 and the short length of the passage 2, the entire mouthpiece is exceedingly small and compact and may be readily carried in the pocket. It is furthermore adapted to be made with great rigidity and solidity so that it is not liable to breakage. Thatit is cheap and durable does not need to be pointed out. The flatform .great intensity which has been developed, at

of the cone renders the mouthpiece absolutely sanitary, since it will not collect the dust and dirt in the first place, and may be wiped ofi with a single movement of the transmitter. v

In Fig.3 I have illustrated a metal collar 6 having't-he standard threads 7 to fit an ordinary transmitter and itself threaded on to a somewhat smaller boss 8 of the mouthpiece, preferably by a thread/ of dilferent pitch, which prevents its accidental removal, although not interfering with its intentional removal when desired.

Another advantage of the present invention is that there is no cup shaped cavity of considerable volume or capacity tending to resonate extraneous noises directly into the mouth of the transmitter. In cities there is a continuous noise from all sorts of distant sources, and if the mouthpiece of the transmitter has a resonating capacity it will pick up and resonate these noises just as a sea shell resonates noises when held to the ear. It is evident that the mouthpiece of the present invention is entirely free from this quality.

In Fig. 4 a form of the invention is illustrated wherein the mouthpiece is made a permanent part of the face plate of the transmitter. The ordinary transmitter face plate is held in place by three or four screws in accordance with standard. practice, and may be readily removed and the form of Fig. 4 substituted. The ordinary or standard face plate may be simply moulded into a unit with the mouthpiece of the present invention if desired. In this way the possibility of stripped threads is avoided and the mouthpiece is not removable so as to be lost, or stolen, or'tampered with. It is moreover even less liable to breakage than the forms of Figs. 1,2, and 3. In fact the life of the mouthpiece would he certainly equal to or greater than the rest of the instrument, and no more thought need be given toits mainte-- nance or replacement than is given to the other parts of the instrument, which is the desideratum which the telephone companies are striving to attain.

While I have described the mouthpiece as made with only a single small aperature at the center, I do not of course desire to be strictly limited to only a single aperture, since it is evident that two or more apertures may be grouped together so compactly in such a way as to give exactly the same effect as has been above described in connection with the single aperture 2.

What I claim is A transmitter mouthpiece having a boss on the rear face of a substantially solid cylindrical body, said body having a conical aperture extending inwardfrom a line near the front peripheral edge to a point near the rear face of the cylindrical body, said mouthpiece having another smaller reversed so s. sonNEBoRN.

Witnesses E. A. Game, Jr., JOHN MAC IN'IYRE. 

